Beam Domain Speed of Sound Estimation via Point Spread Function Analysis

Clinical ultrasound imaging quality highly depends on the accuracy of the speed of sound (SOS) for focusing delay calculation in the process of array beamforming. Although it is commonly assumed to be a fixed value, the SOS in human tissue is unknown and varies widely. This mismatch leads to focusing errors and poor imaging quality. Thus, an optimal SOS estimator is required to obtain optimal imaging quality. Recently, most proposed SOS estimators rely on spatial coherence analysis of the prebeamformed channel domain signals, which are with relatively high computational complexity and are not suitable for application in portable ultrasound. In this work, we propose a novel beam domain SOS estimator using the iterative analysis of point spread function retrieved from beamformed baseband (i.e., IQ) data.